Progression and incidence of myopia among schoolchildren in the post-COVID-19 pandemic period: a prospective cohort study in Shantou, China

OBJECTIVES: To determine the progression and incidence of myopia in Chinese schoolchildren in the post-COVID-19 pandemic period in Shantou, China. DESIGN: Prospective cohort study. SETTING: Shantou Myopia Study, China. PARTICIPANTS: 1-year follow-up data were available for 621 881 schoolchildren (301 999 females). Data on spherical equivalent refraction (SER) were collected. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcomes were myopia progression and incidence. Myopia progression is defined as a change of SER towards the negative direction in the follow-up visit. Incidence is defined as the proportion of schoolchildren who were not myopic but developed myopia in the follow-up study. Age, sex and SER at baseline were evaluated as associated factors for myopia burden, which were defined as the secondary outcomes. RESULTS: Mean progression of SER was −0.35±0.97 D for the population (ranging from −0.06 D at 18 years of age to −0.46 D at 11 years of age), with a rapid myopic progression for students at the age of 10–12 years (−0.50 D in girls and −0.44 D in boys). A myopic shift greater than −0.50 D/year occurred in 256 299 eyes (41.21%). Myopic progression in refraction was associated with the 10–12 years age groups (OR 1.42; 95% CI 1.39 to 1.45, p<0.001), female sex (OR 1.09; 95% CI 1.08 to 1.10, p<0.001) and higher refractive errors at baseline (OR>1.00, p<0.001). The annual incidence of myopia among schoolchildren was 24.85%, with an incidence of 26.69% in girls and 23.02% in boys. CONCLUSIONS: Our study revealed an annual myopia progression of −0.35 D and an incidence of 24.85% among schoolchildren in the post-COVID-19 pandemic period. Myopia progressed rapidly at 10–12 years of age, with −0.50 D in girls and −0.44 D in boys. The incidence was higher for children aged 10–11 years and for girls.